• Korean Journal of Plant Tissue Culture
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• v.25 no.2
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• pp.103-107
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• 1998

Tobacco proembryos were irradiated with 100 Gy of heavy-ion beams($^{14}\textrm{N}$, $^{20}\textrm{Ne}$: 135 Mev/u) after 24 to 96 hours of pollination as a mutagen and screened $\textrm{M}_{1}$ generation for morphological mutants and salt-tolerant plants. Morphological and physiological characteristics of the salt-tolerant plants derived from the irradiated proembryo are discussed in this report. Mutants irradiated proembryos with the beams after pollination produced various kinds of morphological variation. A total of 17 salt-tolerant plants were selected from tobacco cultivar (BY-4) by treatment with $^{14}\textrm{N}$ beam. Shapes of filament and pollen grain of most salt-tolerant plants were abnormal compared with non-irradiated wild type, and seeds weight and fertility obviously decreased. The germination rates of the several $\textrm{M}_{2}$ lines on the saline and the mannitol condition were higher than that of wild type.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.159-165
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• 2018

The seed yield of summer plants is affected by climate change due to high temperature. High temperature during the reproductive growth period decrease pod, seed weight in soybean. This study was conducted at National Institute of Crop Science (NICS) during the growing season. The objective of this study was to determine the effect of high temperature on growth and seed yield responses of soybean varieties using a temperature gradient chamber (TGC). In 2017, the Daewonkong (DWK), Pungsannamulkong (PSNK), and Deapungkong (DPK) were grown in three TGCs. Four temperature treatments, Ta (near ambient temperature), Ta+1 (ambient temperature+$1^{\circ}C$), $Ta+2^{\circ}C$ (ambient temperature+$2^{\circ}C$), $Ta+3^{\circ}C$ (ambient temperature+$3^{\circ}C$), $Ta+4^{\circ}C$ (ambient temperature+$4^{\circ}C$), were established by dividing the rows along which the temperature gradient was created. In all three cultivars, beginning bloom (R1) delayed at elevated temperature in $Ta+4^{\circ}C$. In addition, the days to beginning of seed fill and maturity were longer under higher temperature. The numbers of pod, 100 seed weight, and seed yield increased at elevated temperature in DWK. In contrast, seed yield components of PSNK and DPK were reduced in $Ta+4^{\circ}C$. The results suggest that 100 seed weight and seed size of soybean was low by increased temperature in $Ta+4^{\circ}C$ of PSNK and DPK.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.394-400
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• 1984

In order to find out the possibility of increasing the number of spikelets by changing transplanting date, this study was conducted at Suwon, Yuseong and Jinju in 1979 and 1980. Climatic consumption effect was different depending on location, year, and variety. Number of spikelets can be increased by changing transplanting date due to the decrease of climatic consumption index (C C I) during the reproductive stage. Transplanting date for higher yield and number of spikelets of Tongil was May 25 at Suwon, from May 25 to June 5 at Yuseong and June 5 at Jinju, and in the japonica, it was slightly earlier than that of Tongil in each location. Increasing the number of spikelets and grain yield by the effect of decrease in C C C during the reproductive stage should be considered the percentage of ripened grains.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.317-326
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• 2019

Salinity which is often detected on reclaimed land is a major detrimental factor to crop growth. It would be advantageous to develop an approach for assessment of salinity and drought damages using a non-destructive method in a large landfills area. The objective of this study was to examine applicability of the decision tree classifier using imagery for classifying for spring potatoes (Solanum tuberosum) damaged by salinity or drought at vegetation growth stages. We focused on comparing the accuracies of OA (Overall accuracy) and KC (Kappa coefficient) between the simple reflectance and the band ratios minimizing the effect on the light unevenness. Spectral merging based on the commercial band width with full width at half maximum (FWHM) such as 10 nm, 25 nm, and 50 nm was also considered to invent the multispectral image sensor. In the case of the classification based on original simple reflectance with 5 nm of FWHM, the selected bands ranged from 3-13 bands with the accuracy of less than 66.7% of OA and 40.8% of KC in all FWHMs. The maximum values of OA and KC values were 78.7% and 57.7%, respectively, with 10 nm of FWHM to classify salinity and drought damages of spring potato. When the classifier was built based on the band ratios, the accuracy was more than 95% of OA and KC regardless of growth stages and FWHMs. If the multispectral image sensor is made with the six bands (the ratios of three bands) with 10 nm of FWHM, it is possible to classify the damaged spring potato by salinity or drought using the reflectance of images with 91.3% of OA and 85.0% of KC.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.299-302
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• 1998

V8 juice agar (V8A) has been the most popular and commonly used medium for growth and reproduction of Phytophthora. However, frequently V8 vegetable juice is not available or difficult to obtain in Korea. We therefore developed widely accessible medium to substitute for V8A using domestically available five juices; two carrot (KCJA), two tomato (KTJA) and a vegetable-mix (KVMA). To prepare 10% juice medium, each vegetable juice 100 ml, DW 900 ml, agar 17 g and Ca CO3 0.5∼1.0g were supplemented to adjust pH ca. 6.0 Mycelial growth of P. cactorum and P. capsici on KTJA and KVMA was equally effective as V8A for the growth of P. cactorum, P. capsici, P. drechsleri and P. nicotianae under light. Sporangial production of P cactorum, P. capsici and P. nicotianae on KTJA and KVMA was as good as V8A and slightly better than CKJA, but the difference was insignificant by P. cactorum and P. nicotianae. The four fungi successfully formed oospores on all the media although the numbers were varied among species and media. While KTJA was the best for P. cactorum and P. capsici, V8A was the best for P. capsici and P. drechsleri. However, KCJA stimulated highest number of oopspores of P. nicotianae. Overall results showed that domestically available vegetable juices were highly effective on growth and reproduction of Phytophthora and comparable to V8 juice. Therefore, the domestic juice medium can be successfully replaced V8A in Phytophthora study.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.53-60
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• 1989

The results of the investigation on the effects of plant nutrio-physiological status and reemergence of sudden wilting in rice on the occurrence of sudden wilting were summarized as follows: 1. The occurrence of sudden wilting, degree of damage and occurring time in the investigated variety showed to concur with the results of the previous experiment. 2. Nitrogen and Potassium contents in leaves related an occurrence of sudden wilting at heading stage have a very high negative co-relation (the value is -0.9224 at Yushin and -0.8243 at Milyang 23). 3. Regarding the relation between occurrence of sudden wilting and root activity capacity at the late growth stage, the root activity capacity at productive growth stage showed higher than at reproductive growth stage, which is the same in the two varieties but Milyang 23 is higher than Yushin. It is confirmed that root activity capacity in the two varieties has become very low at reproductive growth stage. 4. The toot activity capacity in the field with potassium showed a small occurrence of sudden wilting and the root activity capacity in the field with no potassium showed a very high co-relation value (the value is 0.8947 at Yushin and 0.7301 at Milyang 23). 5. Regarding the relation between the occurrence of sudden wilting and water evaporation quantity, water evaporation quantity after the heading date has a more direct relation to sudden wilting than that which occurrs prior to the heading date. Water evaporation quantity is higher in the field with no potassium, low leaves and Yushin, than in the field with potassium high leaves and Milyang 23. 6. The starch content in culm of Yushin and Milyang 23 at ripening stage showed high value in proportion to potassium quantity, and the starch content is lower as internode is lower. However, in fourth internode, the starch content is greatly increased in the field with potassium contrasted to the field with no potassium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.1-8
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• 1986

This study was investigated about influence of different cold water irrigation on the nutrient uptake of leaf blade, rachis branches and chaff. Longer duration of cold water irrigation increased total nitrogen content in leaf blade, branches and chaff but decreased the content of phosphate, potassium and silicate. The highest content of total nitrogen and phosphate showed at heading stage, that of potassium in leafblades and branches at heading but in chaff at maturing stage, and that of silicate at maturing stage. Inorganic element content in branches was similar with that in chaff in general. The excessive uptake of nitrogen by cold water irrigation caused decrease in the uptake phosphate, potassium and silicate showing clear nutrient disorder in the blades and chaff. High total nitrogen and low silicate in rice plants seemed to lead to degeneration of branches and spikelets, and to spikelet sterility. Degeneration and sterility appeared to be closely related to nutrient status of branches.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.486-491
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• 2002

Spikelet number and its components of rice plant are closely associated with nitrogen accumulation and biomass production during panicle formation stage. To elucidate this relationship and also compare the differences of the sink formation efficiency among cultivars, spikelet number, its components, nitrogen content, nonstructural carbohydrate content, and plant dry matter were investigated under 5 nitrogen levels with two split application methods and shading treatments by using three rice varieties. The nitrogen amount in shoot at panicle initiation stage and at 15 days after panicle initiation showed significant positive correlation with primary rachis branches per square meter, and that at 15 days after panicle initiation and at heading stage with secondary rachis branches per square meter, Primary and secondary rachis branches per square meter showed positive significant correlation with the shoot dry weight at panicle initiation stage and at 15 days after panicle initiation stage, respectively, The amount of degenerated secondary rachis branches and spikelets per square meter showed significant negative correlation with the dry weight and nonstructural carbohydrate increase of stem during 15days after panicle initiation, and the contents of nonstructural carbohydrate at 15 days after panicle initiation. Spikelets per unit area showed significant positive correlation with nitrogen amount in shoot and shoot dry weight at heading stage. The sink formation efficiency expressed as the spikelet number produced by the unit amount of nitrogen in shoot at heading stage was higher in Nampoongbyeo than Choocheongbyeo and Hwaseongbyeo. Sink formation efficiency was negatively correlated with the dry weight increase of shoot and stem during reproductive stage. but not significantly with that of leaf in all varieties. Sink formation efficiency was not significantly correlated with nonstructural carbohydrate, but was significantly negatively correlated with structural carbohydrate increase during reproductive stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.264-273
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• 2020

'Ilpum', a Korean short-grain mid-late maturing rice cultivar, was developed in 1990, more than 30 years ago. Despite its age, it has been the most widely grown cultivar in the Gyeongbuk province of South Korea for more than 25 years, making it the most important rice cultivar for the people of the Gyeongbuk province. The aim of this study was to analyze the relationship between the rice yield of "Ilpum', the main rice cultivar in the Gyeongbuk province, and climate elements in the Daegu (southern plain area) and the Andong (inland mountainous area) regions in Gyeongbuk, South Korea. The rice yield over the past five years increased by about 13% and 24%, compared to that produced in the late 1990s in Daegu and the early 2000s in the Andong region, respectively. The number of panicles per hill and the grain ripening rate significantly affected rice yield in the 'Ilpum' cultivars in the Daegu region. The faster heading was a factor in the increase in 'Ilpum' rice yield in the Andong region. The air temperature has been rising and sunshine duration has been increasing from the late 1990s to present in both regions. Rice yield was evaluated to understand the effect of climate factors. The rice yields increased owing to the long sunshine duration during the grain-filling stage in both regions. In Andong, increasing the maximum temperature during the vegetative stage increased rice yield. Rising air temperature during the reproductive stage also increased rice yield. In particular, long sunshine hours throughout the whole rice growing period increased the rice yield of this cultivar in the Andong region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.193-203
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• 2019

The aim of this study was to analyze the relationship between rice yield and climate elements in Daegu (southern plain area) and Andong (inland mountainous area) regions. Over the past 20 years, rice yield has increased in both regions. The rice yield of middle and mid-late maturing cultivars in the recent 5 years increased by about 10% and 18%, respectively, compared to that produced in the early 2000s in the Daegu region. In the Andong region, the rice yield of mid-late maturing rice cultivars in the recent 5 years was higher by about 7% than that of the early 2000s. The number of panicles per hill and grain ripening rate significantly affected rice yield in mid-late maturing cultivars. In addition, the grain weight and grain ripening rate significantly affected rice production in middle maturing cultivars grown in the Daegu region. With regard to the middle maturing cultivars, the relationship between grain weight and rice yield had a positive significant correlation in both regions. To understand the effect of climate factors on rice yield, the milled rice yield of several rice cultivars produced over the past 20 years (1999-2018) at both locations, Daegu and Andong, were evaluated. The rice yields increased owing to long sunshine duration during the grain filling stage in the Daegu region. In Andong, rising maximum temperature during the vegetative stage increased rice yield of early and mid-late maturing cultivars. Long sunshine hours increased yield of mid-late maturing cultivars in both regions.